Manpages - CURLOPT_ALTSVC.3

CURLOPT_ALTSVC - alt-svc cache file name

  #include <curl/curl.h>

  CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ALTSVC, char *filename);

Pass in a pointer to a filename to instruct libcurl to use that file as the Alt-Svc cache to read existing cache contents from and possibly also write it back to a after a transfer, unless CURLALTSVC_READONLYFILE is set in CURLOPT_ALTSVC_CTRL(3).

Specify a blank file name (“”) to make libcurl not load from a file at all.

NULL. The alt-svc cache is not read nor written to file.

HTTPS

  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_ALTSVC_CTRL, CURLALTSVC_H1);
    curl_easy_setopt(curl, CURLOPT_ALTSVC, "altsvc-cache.txt");
    curl_easy_perform(curl);
  }

Added in 7.64.1

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

*CURLOPT_ALTSVC_CTRL*(3), *CURLOPT_CONNECT_TO*(3), *CURLOPT_RESOLVE*(3), *CURLOPT_COOKIEFILE*(3),